1. Field of the Invention
The present invention relates to safety flush bolt entrance door systems and more particularly to an entrance door system including a pair of outwardly opening hinged doors mounted in a door frame and provided with a single locking mechanism on a normally active door engageable with a normally inactive door and operably connected through a control mechanism for controlling one or more flush bolt mechanisms on the inactive door for locking the inactive door to the door frame whenever the locking mechanism on the active door is lockingly engaged with the inactive door.
2. Description of the Prior Art
A traditional system for locking up pairs of hinged doors in an entrance door frame is first to secure one of the doors, a normally inactive door, to the frame using a manually operated bolt. Subsequently, the other or normally active door is then lockingly engaged with the inactive door usually with a key operated lock. This system provides basic security, however, it does not provide the needed safety should a mishap such as fire or other panic situation occur within the building. Many building owners are likely to leave the inactive door in a locked or bolted condition during normal business hours, mainly for the purpose of traffic control or for reducing heating and cooling losses. In the event of a panic situation, people within the building cannot usually tell which door of the pair is locked or bolted and which is unlocked. Injuries may result from people trying to get out through a door that is bolted shut. Because of this problem, many codes have specifically proscribed the use of flush bolt locks on an inactive door in a pair of side-by-side entrance doors.
One attempted solution to this problem is provided by multiple point locks in which a single key is utilized to operate a locking system for securing a pair of doors to one another and at least one of the doors to the surrounding door frame when the lock is activated. Another expedient is to provide a bolt mechanism for the inactive door having a visual indicator to show whether it is locked or unlocked. The indicating bolt, however, does not assure that the door is unlocked, and often, such a bolt cannot be unlocked under a load as might be present in a panic situation.
Both of these prior art systems are unsatisfactory for a number of reasons. One reason is that after some usage, a pair of doors in a door frame are seldom perfectly aligned either with the surrounding entrance door frame or with one another and accordingly, a single key operated lock mechanism does not provide enough power or force to move the doors into proper alignment with one another and with the door frame so that the multiple bolts and strike plates may be properly lined up for locking.